How to write a Regex to match all string groups?

For example, find all aa groups in aaa string. This should result in two aa matches, the first one starting at index 0 and the second starting at index 1.

>Solution :

You can use positive lookahead to crossmatch all aa strings in the given aaa string. The regex you are looking for is (?=(aa)).

JS Example

console.log(Array.from("aaa".matchAll(/(?=(aa))/g)).map(i => i[1]))

Python Example

import re

re.findall(r"(?=(aa))", "aaa")  # ['aa', 'aa']